Kerberos Delegation allows for a front-end server to a access back-end resources by allowing a Kerberos ticket to be created for another service on the originating user’s behalf.
Kerberos Delegation can be done as either full delegation or constrained delegation. To set delegation, in Active Directory Users and Computer, go to the properties of an account and select the Delegation Tab.
Trust this user for delegation to any service is full delegation
Trust this user for delegation to specified services only is constrained delegation and which services the front-end server can access needs to be set.